Trump announced he has nominated former Arkansas Gov. Mike Huckabee to be the U.S. ambassador to Israel.

"Mike has been a great public servant, Governor, and Leader in Faith for many years," Trump said in a statement. "He loves Israel, and the people of Israel, and likewise, the people of Israel love him. Mike will work tirelessly to bring about Peace in the Middle East!"

The role, which will need to be confirmed by the Senate, will be a key appointment as tensions remain high in the Middle East.

Trump has officially announced his appointment of Florida Rep. Mike Waltz as his national security adviser.

The president-elect highlighted Waltz's military background in a statement on the appointment, noting that he is the first Green Beret to have been elected to Congress and served in the Army Special Forces for 27 years.

"Mike has been a strong champion of my America First Foreign Policy agenda, and will be a tremendous champion of our pursuit of Peace through Strength!" Trump said in a statement.

The national security adviser is appointed by the president without confirmation by the Senate.

-ABC News' Soo Rin Kim, Kelsey Walsh and Lalee Ibssa

While control of the House has not yet been projected by ABC News, Republicans are inching toward maintaining their slim majority.

But already, Trump has picked several lawmakers to serve in his administration: Rep. Elise Stefanik for United Nations ambassador and Rep. Mike Waltz for national security adviser.

Speaker Mike Johnson, asked about the issue on Tuesday, said he's spoken to Trump about it several times.

"We have a really talented Republican Congress ... Many of them can serve in important positions in the new administration. But President Trump fully understands, appreciates the math here and it's just a numbers game," Johnson said. "You know, we believe we're going to have a larger majority than we had last time."

The speaker added: "I don't expect that we will have more members leaving, but I’ll leave that up to him."

Billionaire John Paulson said Tuesday he does not plan to formally join the administration as the secretary of the U.S. Department of the Treasury, though he said he intends to remain actively involved with Trump's economic team.

"Although various media outlets have mentioned me as a candidate for Secretary of the Treasury, my complex financial obligations would prevent me from holding an official position in President Trump’s administration at this time," Paulson said in a statement.

"However, I intend to remain actively involved with the President’s economic team and helping in the implementation of President Trump’s outstanding policy proposals," he added.

-ABC News' Beatrice Peterson